Re: Tuner for 2011 3500 express van
If I were you I would try and find a local tuner in the area to do a custom tune for you. Most handheld tuners are limiting and severely undertuned so that they are not liable anything that goes wrong, tunes need to be specific to the area you are in.
Find anyone who uses EFI or HPTuners, they ususally charge $150-200 for a tune and they can configure your ECM to whatever options, upgrades and changes you have. You can find custom tuners online or at local speed shops.
2006 Express Duramax 2500